ElD0C·3 lata temu·discussI think those 4 numbers are the youtube "handles", to allow multiple accounts to have the same name.
ElD0C·6 lat temu·discussI'm not 100% sure who's the target audience of this book, frankly. I had the opportunity to read it some time ago and, for someone new to the language/programming, it is clearly difficult to learn from after the first few chapters.